When two systems communicate, a device or an identity using a device in one of the computer systems typically is identified to the other computer system. For example, a device or an associated identity in a client system may be identified to a host system. The identification of a device or an identity may permit a host system to make specific features or information available or unavailable to the device or the identity using the device.
In some computer systems, the identity of a user or a device must be authenticated before the user or the device is permitted to access functions provided by the computer system. User authentication may be based on the presentation of a user name and a password, the combination of which is validated by the computer system. Also, a user or a device may be authenticated using a cryptographic process in which a user identity or a device is proven valid through the use of cryptographic authentication credentials.